London -LRB- CNN -RRB- -- Internet giants signed up Tuesday to a `` zero tolerance '' approach to images of child sexual abuse as the British government announced a new , tougher strategy to find and block illegal content .

Google , Yahoo , Microsoft , Twitter and Facebook were among the firms summoned to a meeting on the issue at 10 Downing Street , the prime minister 's residence , by the UK government 's Department for Culture , Media and Sport .

The summit was called in the wake of two recent UK child murder cases . In each case , the killer had viewed child sexual abuse images and violent pornography on the Internet , sparking calls for action to eradicate such content and protect vulnerable young people .

After the summit , the government said the Internet Watch Foundation -- a watchdog body set up in 1996 -- would have new powers to seek out child sex abuse images , block access to them and remove them .

The watchdog has previously acted after an image of child sexual abuse was reported to it via a hotline . While there are an estimated 1 million unique images of child abuse online , only 40,000 reports are made to the Internet Watch Foundation each year , the Department for Culture , Media and Sport said .

Now , the watchdog will work with a cross-agency government body , the Child Exploitation and Online Protection Centre , known as CEOP , to hunt down such images , the department said .

And the UK 's leading Internet service providers -- Virgin Media , BSkyB , BT and TalkTalk -- have agreed to give Â # 1 million -LRB- $ 1.57 million -RRB- over the next four years to help fund the new approach .

Tuesday 's agreement represents a `` fundamental change '' in the way child sexual abuse content will be tackled , the Department of Culture , Media and Sport said .

`` This will mean more images of child sexual abuse will be tracked down and acted on , '' said Culture Secretary Maria Miller .

`` The abuse of children is absolutely abhorrent -- and that child is further violated every single time an image is circulated and viewed . The IWF and CEOP already do important and valuable work .

`` This agreement will mean these organizations will no longer be limited to reacting to reports received . They will now have the remit and the resources to take the fight to the criminals perpetrating these vile acts . ''

In addition , Internet providers have agreed to introduce by the end of the month special pages to tell users when they try to access a page that has been blocked by the Internet Watch Foundation .

The four main UK Internet service providers will also beef up the parental control options they offer , so that parents can easily restrict Internet access on all devices in their home by the end of the year .

The main cell phone service providers in the United Kingdom also took part in the talks .

All the firms present signed a statement saying : `` We have a zero tolerance approach to the presence of child sexual abuse material on the Internet . ''

Prime Minister David Cameron , speaking to reporters at the Group of Eight summit in Northern Ireland , said he was `` personally committed '' to the battle .

He said he welcomed steps to make sure the big Internet companies `` use their expertise , their brains and their brilliance to get these disgusting images off the Internet much faster . ''

Tuesday 's summit is not the only action taken by Web giants to tackle the scourge of exploitative images online .

Google said Tuesday that it will spend $ 5 million on an effort to wipe pictures of child sexual abuse from the Web and another $ 2 million to research more effective ways to find , report and eradicate the images .

Some of that money will go to the National Center for Missing and Exploited Children as well as the Internet Watch Foundation , said Jacqueline Fuller , the director of Google Giving , in a blog post .

The Web giant also is creating the Child Protection Technology Fund to develop more efficient ways to fight child porn , and already works to tag illegal images and prevent them being found elsewhere .

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UK government summons Internet giants to talks on tackling child sexual exploitation online

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Firms sign up to a `` zero tolerance '' approach to images of child sexual abuse

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Watchdog body is given new powers to seek out and block illegal images

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British Prime Minister David Cameron says he is personally committed to the battle